Is 20lbs in two months realistic?

Yes if you work it's very possible

Nope. It was water weight. When you have 20 pounds to lose you should aim to lose half a pound a week, not more, or it's not healthy at all.

A good chunk of what you lose at first will be water weight, so no. At your size, losing 10 pounds of fat in a month is not healthy.

The 3-4 pounds is a month is a more realistic goal. The initial month always has that water loss going on.

Since Jan 1st til today I have lost 14lbs, but the first 10 came off so fast that I know it was just water - the last 4 have been challenging and I fully anticipate the rest to be just as hard (and harder). Doount on losing that much every month.

Sometimes the numbers don't correlate that closely with what's been predicted. I have my calories set to lose 1.5lbs per week and taking into account water weight I probably initially lost 3lb water and then started losing fat at a rate of less than 1lb per week, more like 0.5.

Our bodies are all different, and for some it's easier to lose than others.

The only thing to be mindful of is that if you're losing that quickly without exercise you may be losing muscle. Maybe try adding exercise and eating more to slow down the rate, or even just eating more!

There are no absolutes in life and this is true here as well. It is absolutely possible to lose ten pounds or more in a month. It's just not easy or simple. Most people throw the following two statements at anyone trying to lose more than 2lbs a week: it's not safe and it's not sustainable.

Whilst there is a degree of truth to both these statements they are not exactly 100% accurate.

The reason it might not be safe is that in order to lose more than 2lbs a week, you will need to be hitting a 1000+ calorie deficit every day which for me would be a limit of 1500 a day. Getting lower than this runs the risk of you not getting enough nutrients, minerals and vitamins and whilst that's no problem in the short term (a few days), will cause problems if you do it on an ongoing basis.

The way I get round this is activity and lots of it. If you are averaging 500-1000 calories a day in extra activity then you have far more scope to limit the calories eaten and still get the nutrients you need. Many people have been skeptical about this but I don't mean you have to be flogging yourself to death in the gym every day. For example, today I have been in the gym pushing weights for half an hour (not power lifting, just high reps low weight), I jogged 3 miles home from work and on the way into work I got off the bus some stops early and walked for half an hour. MFP tells me that was worth 814 calories total. Other days I might swim or go for a very long walk with the kids. Or do a lot of other Non Exercise Activity; trying to keep to 10k steps a day is good and MFP has a step counter I believe. I'm not exhausted and I have had plenty to eat today. On that subject, most of what I'm eating at the moment is either meat, fish vegetables and eggs with some occasional nuts and some protein shakes when I've done a big work out like 6.5 mile run on Sunday, to aid recovery.

My so called water weight does not change as I drink plenty and I work all the major muscle groups to retain my lean mass ( I keep an eye on both). Your muscles are made up of quite a bit of water and when you lose lean mass its this water and some muscle fibre that is lost. If you take steps to avoid this, then what you're losing is not water weight. It's hard but it can be done.

On the subject of sustainability. The speed at which you lose weight has very little to do whether you keep it off, from a point of view of how your body metabolises various fuel sources. If you crash diet/starvation diet, it's highly likely that you are not losing just fat but lean body mass as well (muscle etc). As soon as you start eating half way sensibly the body simply repairs the muscle and other lean mass it may have used, which includes a fair degree of water. If you do it the way I mentioned above, involving some gym work, high protein and eating right then that factor is taken out. There is the factor that starving yourself causes your metabolic rate to slow (how your body uses fuel to keep you alive). Again, if you're eating right, exercising and not skipping food, this shouldn't be an issue.

The other reason is, that it's no good if you go right back to the eating habits that got you overweight in the first place. But no one denies that. Once I finish my 28 Day programme I will ease some carbs back into my diet and ease up on the exercise a bit. If I find I am gaining more than a few pounds I go back on a week of maintainance. If I have more weight to lose, I take a break for a week eating sensibly but up to 2500 a day and light exercise and then start again. In these week breaks, I have not gained any weight and the second 28 days has been as effective as the first.

It's definitely easier to change your diet and exercise lifestyle first to what you plan to make it long term and see the weight come off slowly but that doesn't mean it's the only way.

You will need to so a degree of planning both meal planning, activity planning (which resulted in me buying a small amount of equipment and apps etc) and some discipline but I have been able to do this for 28 day stretches before and lost anywhere between 12 and 20 pounds in that time with no ill effects that I could see. I've done this three times now. My need for this is that I play a lot of sport and when I got a couple of major injuries (broken leg etc) I have put on quite a bit of weight. There's no real reason to do it this way rather than slow and steady, I just like to get back to what I call my fighting weight as quickly as possible. Some people have said to me that it's best to get it over with as soon as possible but it is not a matter of 'over', you need to permanently change the habits that got you overweight in the first place.

A lot of posters have referenced water weight. I think I have covered this if I have understood the term correctly. I don't disagree with anything that's been said and its a thin window but you can lose weight quickly and ensure most if not all is fat if you maintain LBM. If anything my LBM goes up slightly during these 28 day sessions. I imagine people will say it's not possible, but I've done it 3 times now. Also, think of all those Biggest Loser programmes on TV, those guys are losing over a pound a DAY for a six month period or longer, and they are looked after by a team of dieticians and exercise experts so are making sure the LBM is protected and sufficient nutrition is being taken on, and that can't be water weight, it's just not possible.

So in summary, definitely possible to do safely and in a sustainable way BUT it takes 28 days of will power, careful planning, being no stranger to exercise, pushing weights and activity and discipline.

Good luck!

I lost quite a bit in my first month...most of which was really in the first couple of weeks...it slowed down dramatically after that due to the fact that a lot of my big, early losses were drops in water weight and having less waste in my system from consuming less.

Your goals to lost 3-4 Lbs per month are very realistic...expecting to lose 10 again this month is probably not so realistic unless you're really depriving yourself of calories and substantially under-eating.

These kinds of losses are more sustainable for people who are obese/morbidly obese as they have the fat stores to support large energy deficits...without those fat stores, you're not going to be able to maintain that pace...you also run the risk of losing a greater % of muscle and other lean mass in the process.